Background: The dose-related effects of pa ent setup errors on bio-physical indices were evaluated for the conven onal wedge (CW) and field-in-field (FIF) whole breast irradia on techniques (WBI). Materials and Methods: The treatment plans of 10 pa ents receiving le' WBI were retrospec vely selected for evalua on. The bio-physical effects of dose varia ons were evaluated by shi'ing the isocenters and gantry-angles of the treatment plans. Dose-volume histograms of the planning target volume (PTV), heart, and lungs were generated, and the conformity index (CI), homogeneity index (HI), tumor control probability (TCP), and normal  ssue complica on probability (NTCP) were determined. Results: The D95 of the PTV for an “ isocenter shi' plan” with a posterior direc on decreased by approximately 15%, and the TCP of the PTV decreased by approximately 50% for the FIF technique and by 40% for the CW; however, the NTCPs of the lungs and heart increased for both techniques. Increasing the gantry-angle decreased the TCPs of the PTV by 24. 4% (CW) and by 34% (FIF). The NTCPs of the lungs and heart for the two techniques differed by only 3%. The CIs and HIs for the CW case were higher than the corresponding values obtained for the FIF case. Significant differences were observed between the two techniques (p<0. 01). Conclusion: Our results revealed that the biophysical proper es of the FIF case were more sensi ve to setup errors than those in the CW case. The radiobiological-based analysis could be detected significant dosimetric errors and provided a prac cal pa ent quality assurance method for guiding the bio-physical effects.

Introduction Patient set-up optimization is required in radiotherapy to fill the accuracy gap between personalized treatment planning and uncertainties in the irradiation set-up. In this study, we aimed to develop a new method based on neural network to estimate Patient geometrical setup using 4-dimensional (4D) XCAT anthropomorphic phantom. Materials and Methods To access 4D modeling of motion of dynamic organs, a phantom employs non-uniform rational B-splines (NURBS)-based Cardiac-Torso method with spline-based model to generate 4D computed tomography (CT) images. First, to generate all the possible roto-translation positions, the 4D CT images were imported to Medical Image Data Examiner (AMIDE). Then, for automatic, real time verification of geometrical setup, an artificial neural network (ANN) was proposed to estimate Patient displacement, using training sets. Moreover, three external motion markers were synchronized with a Patient couch position as reference points. In addition, the technique was validated through simulated activities by using reference 4D CT data acquired from five Patients. Results The results indicated that Patient geometrical set-up is highly depended on the comprehensiveness of training set. By using ANN model, the average Patient setup error in XCAT phantom was reduced from 17. 26 mm to 0. 50 mm. In addition, in the five real Patients, these average errors were decreased from 18. 26 mm to 1. 48 mm various breathing phases ranging from inhalation to exhalation were taken into account for Patient setup. Uncertainty error assessment and different setup errors were obtained from each respiration phase. Conclusion This study proposed a new method for alignment of Patient setup error using ANN model. Additionally, our correlation model (ANN) could estimate true Patient position with less error.

Introduction: The aim of this study was to determine the accuracy of two different immobilization methods in Patient positioning in cranial radiotherapy. The six-dimensional (6D) target localization accuracy of using a dedicated stereotactic mask was compared with that of a conventional head mask by the ExacTrac system. Material and Methods: A total of 56 Patients with cranial lesions were included in this study (26 Patients with a dedicated stereotactic mask and 30 subjects with a conventional head mask). The ExacTrac image-guided positioning system was utilized to obtain daily translational and rotational Patient positioning displacement from the intended position. The 6D setup data was analyzed to obtain population mean, systematic and random errors, and three-dimensional (3D) vector shifts in all the Patients. Results: The population mean values of setup errors were comparable with both immobilization systems; however, the spread as indicated by population systematic and population random errors was more in the use of a conventional head mask. The mean values of the 3D vector shifts were 2. 09± 1. 00 and 4. 51± 3. 38 mm with the use of a dedicated stereotactic mask and conventional head mask, respectively. The frequency distribution of maximum rotational deviation and statistical analysis demonstrated a significant difference in immobilization accuracy between stereotactic immobilization and 3-clamp immobilization (P<0. 05). Conclusion: The results revealed that there was a significant reduction in target positioning errors with a dedicated stereotactic mask, compared to that with a conventional cranial mask. Furthermore, a dedicated stereotactic mask is required to keep rotational deviations within system correctable limits.

Introduction: Radiation therapy involves a multistep procedure; therefore, the error in Patient set up is an inherent part of the treatment. Main purpose of this study was to determine the clinical target volume (CTV) to planning target volume (PTV) in head and neck cancer Patients. Material and Methods: A total of 15 Patients who had daily portal images during the treatment courses were randomly selected in the present study. Systematic (Σ ) and random (σ ) errors were evaluated in three directions. The Isogray treatment planning system and Elekta linear accelerator were used in this study. Moreover, we had used MOSIAQ software as a record and Verify system. setup margins were calculated using three published margin recipes, including the International Commission on Radiation Units and Measurements (ICRU) report 62, as well as Stroom’ s and van Herk’ s formulae. Results: Average magnitude of the translational errors was reported between 0. 7 and 10 mm. The systematic and random errors for head and neck cancer Patients were 3. 55 (2. 58-4. 52) and 1. 83 (1. 56-2. 10) mm, respectively. According to the ICRU report 62, as well as Stoorm’ s and van Herk’ s formulas, the required margins to cover the target were obtained within the ranges of 3. 1-4. 9, 6. 4-10. 5, and 7. 7-12. 7 mm, respectively. Conclusion: According to the results of the present study, 6. 5-10. 5 mm extension in CTV to PTV margin can ensure that 90% of the head and neck cancer Patients will receive a minimum cumulative CTV dose higher than or equal to 95% of the prescribed dose.

In this paper, we consider the estimation of the stress-strength reliability of a coherent system. The distributions of stress and strength random variables are the members of a general class of distributions. For a series-parallel system, the reliability of the stress-strength model is estimated using the maximum likelihood estimation, asymptotic confidence interval, uniformly minimum variance unbiased estimation, and Bayes estimation. Also, simulation studies are performed, and two real data sets are analyzed.

Purpose In recent years, significant energy consumption and facing global warming have led to concern worldwide. Therefore, governments have turned to deterrent actions such as imposing daily tariffs in different intervals to tackle energy consumption. This article addresses unrelated parallel machine energy-efficient scheduling problems by considering sequence-independent setup times and energy consumption tariffs. The objective function is that jobs should be assigned to machines and processed in different intervals so that the cost of consumed energy becomes as less as possible. It should be noted that the assumed sequence-independent setup times are addressed in two different modes, setup times jointed to processing time and setup times disjointed from processing time. Design/methodology/approach: To optimize the total energy consumption cost in unrelated parallel machine scheduling problems with sequence-independent setup times jointed to processing time and disjointed from processing time, mixed-integer linear programming (MILP) models have been proposed from two different points of view. The first model has been formulated according to the predecessor jobs of a special job, while the second model has been conducted based on the immediate predecessor job. Also, a fix and relax heuristic (FRH) algorithm has been conducted to solve large-scale instances. All mathematical models and the heuristic algorithm have been coded in the Visual C# 2017 environment and implemented using the CPLEX 12. 8 Concert Technology on a PC with 32GB RAM and Intel Corei7 4. 0 GHz CPU (4 cores). Also, a sizeable number of instances have been solved to evaluate the efficiency of mathematical models and the heuristic algorithm and to ensure their accuracy. Findings According to numerical analysis, both mathematical models solved the instances of up to 20 jobs and 80 machines optimally for sequence-independent setup-times jointed to processing time, and sequence-independent disjointed from processing time problems. However, generally speaking, the mathematical model based on predecessor jobs was more efficient than another mathematical model, especially in terms of run time. Moreover, the proposed fix and relax-based heuristic algorithm solved instances of up to 20 machines and 190 jobs for the disjointed setup times problem, and up to 20 and 220 instances for the jointed setup times problem. It should be noted that all instances were generated analogously to the literature. Research limitations/implications A vast number of exogenous factors contributed to the scheduling problems in the real world, which can disturb the scheduling process easily, frequent power outages, machine breakdown, and operator absence. Besides, considering all the real world's possibilities raises extreme complexity in problems. Therefore, similar to other studies, some assumptions were considered as follows:-machines are always available at all times,-idle is allowable for machines,-the energy consumption rate of various machines is different for each job,-each machine's energy consumption rate during processing and setups is different for each job, it is assumed as constant,-preemption is not allowed in the job's processing and setups,-all jobs are available at the beginning of the planning horizon,and-each machine can process or do the setup for only one job at a time. Practical implications Given that unrelated parallel machines are one of the most practical scheduling environments, this article can be effective in production sites and operation lines that contain such a kind of machine. Besides, unrelated parallel machines cover identical and related parallel machines. Consequently, this paper is the building blocks of cost-effective and environmentally friendly scheduling programs. Also, the application of unrelated parallel machines is not merely restricted to production problems. In other words, unrelated parallel machine scheduling problems can be used in other real-world cases, such as airplane scheduling and elevator scheduling. Originality/value-In this paper, unrelated parallel machine energy-efficient scheduling has been addressed considering sequence-independent setup times. Since it was a common belief that sequence-independent setup times could be included in processing times, sequence-independent setup times have been neglected so far. However, in this innovative study for the first time, an unrelated parallel machine energy efficient problem was investigated with sequence-independent setup times. Mathematical programming models and a heuristic algorithm were proposed for such a practical problem.